Entrainment stacks need to work in the outdoor environment in which they are installed. As crosswinds accelerate, it is important for public safety that stacks maintain designed dilution ratios. Plasticair has now fully addressed dilution and crosswinds.

Our originally designed uni-passage SKYPLUME G1 has wind deflection characteristics inherent to the design on two sides. Our further developed SKYPLUME G2, has greatly enhanced this design feature by adding wind deflection panels. This is very important and ensures that dilution ratios are constant up to 41 MPH with a nozzle velocity of two times crosswind speed.



• Our nozzle is a constant velocity nozzle, meaning that the area is constant from inlet to outlet which translates to virtually no pressure loss. Although this is not a factor dealing with entrainment, it is very beneficial to the whole system as it will result in lower electrical horse power requirements and lower sound output, all this while maintaining a minimum 200% dilution ratio up to 41 MPH.

• The SKYPLUME G2 is constructed of solid UV stabilized FRP and can structurally withstand winds up to 150 MPH. Inlets are round and can be fitted with a rectangular transition to fit any fan. Plasticair is proud to offer this product as a unit by itself for component system integration. Also, Plasticair is well experienced and an industry Leader in providing full manifold multi or single fan systems with AMCA Air and Sound Certified Fans.

• SKYPLUME G2 configurations are as follows:

Stacks supplied independent and constructed of FRP. Also available for special order in coated steel or 316 ss

SWSI swing-out easy access maintenance friendly arrangements 1,4,9. Fan constructed of coated steel and SKYPLUME G2 constructed of FRP.

SWSI centrifugal arrangements 1,4,8,9,10. Fan and SKYPLUME G2 constructed of FRP.

SWSI centrifugal arrangements 1,4,8,9,10. Fan constructed of coated steel, SKYPLUME G2 constructed of FRP.

Inline mixed flow arrangements 9. Fan and SKYPLUME G2 constructed of FRP.

Inline mixed flow arrangements 9. Fan constructed of coated steel and SKYPLUME G2 constructed of FRP.

Testing Methodology

“Plasticair is taking a TRANSPARENCY approach into High Plume Dilution Testing”.

Plasticair has taken the leadership roll regarding the testing of high plume dilution stacks. We have included our testing methodology and results which were conducted and designed by one of North Americas leading Fluid Dynamic Consulting Engineering Firms: RWDI ( Rowan Williams Davies & Irwin Inc ) in order that Engineers and Owners can evaluate the thoroughness of Plasticair methods and really understand what they are specifying, and more importantly, they can see reliable scientific proof of the induction and entrainment characteristics of the product. For further information please review our PDF file attached:

We urge that the Engineering Community specify proper testing for this very important aspect to HVAC design. These stacks are applied to exhaust air streams that contain dangerous and sometimes contiguous molecules that must be properly diluted and evacuated away from the public. Engineers specifying these types of systems should consider manufacturers that have tested their stacks as thoroughly as the Transparency HPD test and also specifying manufacturers that provide equipment with the AMCA Air and Sound Seal when dealing with laboratory exhaust and public safety.


Acceptable Manufacturers: Plasticair Inc., SKYPLUME G2

• Wind Resistant Fan Outlet Nozzle and Windband

• Material of construction will be UV stabilized solid FRP and the manufacturer will provide a 20 year warranty against equipment failure due to rust. The nozzle windband assembly will be structurally designed to withstand 150 MPH winds. Design calculations will be presented to the specifying Engineer for review and approval. FRP construction will be Derakane 510-C and will have a 0-25 flame spread. The Stack assembly will comply with the requirements of ANSI Z9.5.

• The nozzle assembly will be designed to induce outside air by a venturi effect and also entrain air to provide dilution ratios that are not less than 192% and average 205% throughout crosswind speeds up to 41 MPH. For safety reasons, the stack will also be designed and thoroughly tested to resist downwash within the wind band caused by crosswind pressure/vortices up to 41 MPH as a design standard. Stack design shall be stable enough to accommodate internal downwash protection against any wind speed using a nozzle velocity that is two times cross wind speed. Stack scaled design must undergo physical wind tunnel testing to the following criteria:

1) Testing to confirm dilution results from crosswind effect from any position 360 degrees around the stack and three speeds up to 20 MPH.

2) Chemical concentration testing with a minimum of 65 pitot tube sampling points evenly distributed in a radial direction located level with the stacks physical highest point. Parts per million input vs. parts per million output will be used to determine dilution ratio. For large sizes, a minimum of 79 pitot tube sampling points per square foot are required.

3) Tested with at least 2 pitot tube sampling points located at base of windband for monitoring down wash against crosswinds up to 20 MPH. At least one pitot tube will be placed down stream of the crosswind.

4) Corresponding velocity testing with a minimum of 65 pitot tube sampling points

5) All wind tunnel testing completed as listed above, stamped by a reputable third party Fluid Dynamics Consulting Engineering Firm.